Apparatus for the fractional condensation of metal vapors in a condenser rotating about a horizontal axis



7 APPARATUS FOR THE I A CONDEN A. LEYS ONAL TATIN Nov. 19 1935.

NER 2,021,365 CONDENSATION OF METAL VAPORS IN 6' ABOUT A HORIZONTAL AXIS i led July 25, 19%

II l 19 A 13 Fag 1 WW Patented ,Nliv. 19, 1935 UNITED TATE TEwor+na CONDENSERROTAWG ADOPT m- ZONTAL AXIS 'Ai-thur Levon er, MagdeburgGei-many, asslgnor to the firm Fried. Krupp Gruaonwerk Aktiengesellschal't, ll/Iagdelmrg-Buclra.l i, Germany Application July 23, 1934, Serial No. 136,603

In Germany July 31,1933 7 4 claims. (01.26'6-1-8) It is known to use condensers rotating about a" horizontal axis for, the condensation of metal vapors. This constructional form of the condenser ismainly applied when the distillation of the metals is carried out in rotating muiiles.

- When carrying out such a distillation process,

for example in-the distillation of zinc, it is. im-

possible to prevent metals being distilled, in addition to the main metal, whose boiling point lies lower than that of the main metal, for example of cadmium. Moreover, experience has shown that, to a certain extent, those metals are also distilled at the same time whose boiling point is higher than that of the main metal, for example 35 lead. Furthermore, owing to the ready developmentoi the distillation gases, foreign admixtures, such as ore dust, coke dust and the like,

are as a rule contained in the distillation gases.

The object ofthe invention is to produce a form of condenser which renders it possible to obtain a pure metal condensate from these highly impure gases of distillation According to'the invention 'in apparatus for the fractional condensation of metal vapours in a condenser rotating about a horizontal axis the condenser is subdivided into several compart- 5 ments by the building in of one or more 'damming rings whereby the metal baths condensed in the individual compartments remain separated from one another and the metal vapors -to be condens'ed successively traverse theindividual compartments.

A constructional errample of a" furnace installation suitable for carrying out the process is illustrated .in the accompany n drawing, wherein: y v

Figure 1 is a longitudinal section, and

Figure 2 a cross-section.

In both figures, l is the outer condenser jacket internally lined with a heat insuiatlon jacket 2. In Figure 1, the distillation gases enter through the aperture 3. The waste gases of the condenser leave at 4. Two damming rings 5 and 6 are fitted in the condenser, which-are so constructed that the metal baths I, 8 and 9 accumulated in the compartments A, B and C cannot,come in contact with one another in any positicn' of the condenser. For the periodical drawing on of the metal baths the apertureslll, H and H are provided. In the wall 2 of the condenser, devices l3, I4 and I5 are provided which render possible, by the supply or dissipation of heat, the adjustment of the temperatures required'fer the inbe necessary, electric heating is preierable while vapors leave the condenser with a small portion of the zinc. The recovery of these metal vapors dividual compartments. Should'a supp of heat 7 for the dissipation of heat, which is mainly necessary, the installation of cocling pipes at l3, M and I 5 is preferable. Insteadlof by cooling pipes, cooling can be 'efiected by cooling the outer jacket to difi'erent degrees with a corresponding a dimensioning of the condenser lining. The metal vapors entering at 3 are, in the chamber A, brought by corresponding coolingto a temperature stage which approximately corresponds to the boiling point of the main metal. In the con- 10 densation of zinc vapors, which carry lead and cadmium vapor in addition to flue dust, a temperature of about 900 to 950 is provided in the chamber A. At this temperature, the distilled lead vapor is condensed to correspond to the low iii vapor pressure of the lead at this temeprature. Furthermore, a certain portion of the zinc is condensed, particularly if the temperature is maintained at about 900.- The mist drops composed of lead vapor and zinc vapor forming in the cham- 20 her A lead to the depositing of the dust carried along, so that in the bottom of the chamber A a metal bath is formed which consists of lead and small portion of zinc and practically comgletely contains the impuritiesmechanically car-' 25 ried along. The distillation gases purified in this manner enter the chamber B, where the temperature is so far lowered that the main metal, in the present instance zinc, is condensed therein, which practically means a temperature of 600". At 30 this temperature, the cadmium vapor cannot yet becondensed, but passes with asmall quantity of zinc vapor into thechamber C, where acadmium-zinc alloy is deposited by further temperature reduction. If novalue is attached to the 35 recovery oi. this cadmium-zinc alloy, the arrang'ement of a second damming ring 6 is not, necessary and the temperature of the chamber enlarged by C is made such that at 4 the cadmium the fluid metal bathin this compartment is carried up by the wall andthen, when freely falling, is repassed through the gases. For this purpose, the inner wall of the condenser is provided with 1 'blad or proiections constructed in themanner of blades, as illustrated in Figure 2, which shows a section through the chamber A according to the line I -I. The projections in the inner wall of the condenser are not only able to carry a por-- tion of the fluid metal upwards with them in their rotational'motion, but the condensatitm of 1 the metals from the gases takes place for the greater part thereon; whereby the drops forming then also fall through the gaseous'current. The contact surface'between the gaseous current and the metal bath of the individual chambers serv'-. ing as washing liquid, in particular or the chamber. A, may be substantially increased by placing in the chamber or chambers filling bodies of any desired nature which are such that they are very permeable to gas, the portions of metal carried along then more or less coating the surface of these filling bodies and returning substantially slower into the bath. From the standpoint of the recovery of the principal metal in the main condensing chamber B, the chamber A is a fore chamber in which all impurities are removed from the mixture of vapors which would otherwise condense or deposit in the chamber B. The portion of the main metal, or example of zinc,

condensed in the individual chambers may be accurately regulated by adjustment oi the temperature. in the different chambers. For example,

if the temperature of the chamber'istemporarily so low thata disproportionately greatpart of the zinc is condensed therein, a renewed vaporization of this zinc may be brought about by periodically superheating the chamber. 11 the 0001-" ingin the individual chambers through the wall solid or fluid lead containing zinc may be introduced into this chamber. A distillation of this added metal then takes place in'the chamber,

' which causes a corresponding reduction of the temperature to the boiling point of the zinc. The

supply of this metal in fluid form may, for example, take lace through the spiral it, which in Figure 1 is placed absutthe condenser at comartme'nt A. The 'fluid metal situated in the trough i1 is taken up by .a conveying device it during the rotational .motion 01' thecondenser and passes through the pipe. I! into 'the interior of the compartment A. In each position of the condenser exclusion of air is effected by the fluid metal situated in the individual windings of thespiral. If necessary, valves may be provided in the spiral, which may be periodically opened or closed for the regulation of the supply of metal. 1

manner, also be used for the fractional condensa- The hereinbetore described condenser for the condensation oi zinc vapor may, in a similar tion of other metal vapors, for example for fractional distillation oi arsenic and antimony vapors, 5; magnesium, aluminiumvapors, lead and silver vapors and the like.

I claim:

1. In a metal vapor condenser for separately recovering a principal metal from mixed, vapors ii) containing a higher boiling point metal, a rotary' drum, a damming ring dividing said drum into a main condensing chamber and a fore chamber, means for tumbling a bath of the higher boiling point metal through the atmosphere or said fore 15 chamber, and means to regulate the temperature of said bath sufliciently high to keep the principal metal vaporized in said fore chamber but low enough to condense the vapors of the higher boiling point metal in said mixture.

2. In a condenser for recovering a metal from impure and dusty vapors containing the vapor of the metal to be recovered, means forming a plurality of chambers communicating by a gas passage,- means for letting the impure vapors into the first of said chambers, temperature regulating meansior maintaining said first chamber expose a large surface thereof .to said impure vapors to entrain dust and accelerate condensa- 35. tion of vapors of boiling point higher than that of the metal to be recovered.

3. In a condenser for separately recovering from mixed metal vapors a metal of lower boil- 1 8 point than another ,metal contained in the 40 mixture, means forming a plurality of communicating chambers, means for admitting the mixture of vapors to the'flrst of said chambers, temperature controlling means adapted to maintain said first chamber substantially at the boiling point of said metal of lowerboiling point and a subsequent chamber at a temperature below the boiling point of said metal of lower boiling point,

and-means for spreading out overa large surface metal condensed in said first chamber to entrain solid impurities carried'a'long with the metal vapors and accelerate condensation of the higher, boiling point metal.

4. Apparatus as described in claim-2, wherein said condenser comprises a rotary drum subdividcd by centrally apertured damming rings, the

'walls of said first chamber being provided with projections adapted to raise the '1i(1llidill said chamber and pour it through the atmosphere of said chamber; p

- ARTHUR 

